Business doesn't have to mean that sort of business. Some guy making $3000 a month selling t-shirts and coffee mugs on etsy has, what I would think of, as a good business. Someone opening up a hotdog stand making $4000 also has a good business.
I noticed this in Zambia, lots of people standing by the side of the road selling soda pop and cigarettes or dried fish, or whatever they could get their hands on. Great businesses, great ideas, I'm glad they're doing it and I commend them for it.
The signs this article talks about are extremely limiting, to the point where the author is saying most people shouldn't bother. I think they apply for starting a big disruptive tech startup. I don't think they apply to an etsy store or hot dog stand, and those are viable and fairly easy to reach businesses. Personally I'd much rather focus on the easily attainable later sort of business rather than focus my time and energy in a quixotic effort to try and be the next Musk or Zuckerberg.